docs: def load_weights(self):
          """
          Load weights by evaluating self.network_weights_loader, if needed.
  
          After calling this, self.network_weights_loader will be None and
          self.network_weights will be the weights list, if available.
          """
          if self.network_weights_loader:
              self.network_weights = self.network_weights_loader()
              self.network_weights_loader = None